U.S. patent application number 16/271115 was filed with the patent office on 2019-06-06 for non-friction coupling and control assembly, engageable coupling assembly and locking member for use in the assemblies.
This patent application is currently assigned to Means Industries, Inc.. The applicant listed for this patent is Means Industries, Inc.. Invention is credited to John W. Kimes.
Application Number | 20190170198 16/271115 |
Document ID | / |
Family ID | 66658978 |
Filed Date | 2019-06-06 |
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United States Patent
Application |
20190170198 |
Kind Code |
A1 |
Kimes; John W. |
June 6, 2019 |
Non-Friction Coupling and Control Assembly, Engageable Coupling
Assembly and Locking Member for Use in the Assemblies
Abstract
An overrunning, non-friction coupling and control assembly, an
engageable coupling assembly and locking members for use in the
assemblies are provided. A centroid or center of mass of at least
one of the locking members is offset from a pivot axis of the
locking member so that as the locking member moves from an engaged
position, a moment arm of the centroid relative to the pivot axis
decreases from a maximum value to substantially zero in a
disengaged position to facilitate disengagement of the locking
member at high rotational speeds.
Inventors: |
Kimes; John W.; (Wayne,
MI) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Means Industries, Inc. |
Saginaw |
MI |
US |
|
|
Assignee: |
Means Industries, Inc.
Saginaw
MI
|
Family ID: |
66658978 |
Appl. No.: |
16/271115 |
Filed: |
February 8, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15712651 |
Sep 22, 2017 |
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16271115 |
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62453578 |
Feb 2, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16H 3/006 20130101;
F16D 23/0606 20130101; F16D 23/02 20130101; F16H 2063/3053
20130101; F16D 41/125 20130101; F16H 2063/305 20130101; Y10T
74/19251 20150115; F16D 27/118 20130101; F16H 63/304 20130101; F16D
11/14 20130101; F16D 41/14 20130101; F16D 41/16 20130101; F16H 3/10
20130101; F16D 27/004 20130101 |
International
Class: |
F16D 41/12 20060101
F16D041/12; F16D 11/14 20060101 F16D011/14; F16D 41/16 20060101
F16D041/16 |
Claims
1. A locking member for controllably transmitting torque between
first and second coupling members of a coupling assembly, the first
coupling member including a coupling face having a pocket which is
sized and shaped to receive and nominally retain the locking
member, the locking member comprising: a member-engaging first end
surface; a member-engaging second end surface; and an elongated
main body portion between the end surfaces, the main body portion
being configured to enable pivotal motion of the locking member
about a pivot axis, the end surfaces of the locking member being
movable between engaged and disengaged positions with respect to
the coupling members during the pivotal motion whereby one-way
torque transfer may occur between the coupling members and wherein
a centroid of the locking member is offset from the pivot axis so
that as the locking member moves from the engaged position, a
moment arm of the centroid relative to the pivot axis decreases
from a maximum value to substantially zero in the disengaged
position to facilitate disengagement of the locking member.
2. The locking member as claimed in claim 1, wherein the main body
portion includes a projecting ball-shaped portion to enable the
pivotal motion.
3. The locking member as claimed in claim 1, wherein the locking
member is a radial locking member.
4. The locking member as claimed in claim 2, wherein the pivot axis
is located at substantially a center of the ball-shaped
portion.
5. The locking member as claimed in claim 1, wherein the main body
portion includes a projecting ball-shaped portion offset from the
centroid and adapted to be received within a socket portion of the
first coupling member to enable the pivotal motion, the first
coupling member being adapted to be pivotally connected to the
locking member via the ball-shaped portion.
6. The locking member as claimed in claim 3, wherein the locking
member is a strut.
7. The locking member as claimed in claim 6, wherein the strut is a
ball-socket strut.
8. An engageable coupling assembly comprising: first and second
coupling members, the first coupling member having a coupling face
with a pocket which is sized and shaped to receive and nominally
retain a locking member, the locking member including: a
member-engaging first end surface; a member-engaging second end
surface; and an elongated main body portion between the end
surfaces, the main body portion being configured to enable pivotal
motion of the locking member about a pivot axis, the end surfaces
of the locking member being movable between engaged and disengaged
positions with respect to the coupling members during the pivotal
motion whereby one-way torque transfer may occur between the
coupling members and wherein a centroid of the locking member is
offset from the pivot axis so that as the locking member moves from
the engaged position, a moment arm of the centroid relative to the
pivot axis decreases from a maximum value to substantially zero in
the disengaged position to facilitate disengagement of the locking
member.
9. The assembly as claimed in claim 8, wherein the main body
portion includes a projecting ball-shaped portion to enable the
pivotal motion.
10. The assembly as claimed in claim 9, wherein the first coupling
member includes a socket portion to receive and retain the
ball-shaped portion at a ball and socket interface and to enable
the pivotal motion.
11. The assembly as claimed in claim 8, wherein the locking member
is a strut.
12. The assembly as claimed in claim 11, wherein the strut is a
ball-socket strut.
13. An overrunning coupling and control assembly comprising: first
and second coupling members, the first coupling member having a
first face with a pocket which is sized and shaped to receive and
nominally retain a locking member and a second face having a
passage in communication with the pocket to communicate an
actuating force to the locking member to actuate the locking member
within the pocket so that the locking member moves between engaged
and disengaged positions, the locking member including: a
member-engaging first end surface; a member-engaging second end
surface; and an elongated main body portion between the end
surfaces, the main body portion being configured to enable pivotal
motion of the locking member about a pivot axis, the end surfaces
of the locking member being movable between the engaged and
disengaged positions with respect to the coupling members during
the pivotal motion whereby one-way torque transfer may occur
between the coupling members and wherein a centroid of the locking
member is offset from the pivot axis so that as the locking member
moves from the engaged position, a moment arm of the centroid
relative to the pivot axis decreases from a maximum value to
substantially zero in the disengaged position to facilitate
disengagement of the locking member from the second coupling
member.
14. The assembly as claimed in claim 13, wherein the main body
portion includes a projecting ball-shaped portion to enable the
pivotal motion.
15. The assembly as claimed in claim 14, wherein the first coupling
member includes a socket portion to receive and retain the
ball-shaped position at a ball and socket interface and to enable
the pivotal motion.
16. The assembly as claimed in claim 13, wherein the locking member
is a ball-socket strut.
17. The assembly as claimed in claim 13, further comprising a
linear actuator received within the passage to provide the
actuating force.
18. The assembly as claimed in claim 17, wherein the linear
actuator comprises a solid plunger which moves between first and
second axial positions to control an operating mode of the
assembly.
19. The assembly as claimed in claim 17, wherein the locking member
is biased to move from the engaged position towards the disengaged
position by a biasing member.
20. The assembly as claimed in claim 15, further comprising a
return spring to exert a spring force on the locking member in
opposition to the actuating force and a friction force at the ball
and socket interface.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 15/712,651 filed Sep. 22, 2017, which claims
the benefit of U.S. provisional application Ser. No. 62/453,578
filed Feb. 2, 2017.
TECHNICAL FIELD
[0002] This invention relates to:
[0003] 1) engageable non-friction coupling assemblies such as
radial coupling assemblies;
[0004] 2) overrunning, non-friction coupling and control assemblies
such as radial coupling and control assemblies; and
[0005] 3) locking members for controllably transmitting torque
between coupling members of non-friction coupling assemblies such
as radial coupling assemblies.
Overview
[0006] A typical one-way clutch (OWC) consists of an inner ring, an
outer ring and a locking device between the two rings. The one-way
clutch is designed to lock in one direction and to allow free
rotation in the other direction. Two types of one-way clutches
often used in vehicular, automatic transmissions include:
[0007] Roller type which consists of spring loaded rollers between
the inner and outer race of the one-way clutch. (Roller type is
also used without springs on some applications); and
[0008] Sprag type which consists of asymmetrically shaped wedges
located between the inner and outer race of the one-way clutch.
[0009] The one-way clutches are typically used in the transmission
to prevent an interruption of drive torque (i.e., power flow)
during certain gear shifts and to allow engine braking during
coasting.
[0010] Controllable or selectable one-way clutches (i.e., OWCs) are
a departure from traditional one-way clutch designs. Selectable
OWCs add a second set of locking members in combination with a
slide plate. The additional set of locking members plus the slide
plate adds multiple functions to the OWC. Depending on the needs of
the design, controllable OWCs are capable of producing a mechanical
connection between rotating or stationary shafts in one or both
directions. Also, depending on the design, OWCs are capable of
overrunning in one or both directions. A controllable OWC contains
an externally controlled selection or control mechanism. Movement
of this selection mechanism can be between two or more positions
which correspond to different operating modes.
[0011] U.S. Pat. No. 5,927,455 discloses a bi-directional
overrunning pawl-type clutch, U.S. Pat. No. 6,244,965 discloses a
planar overrunning coupling, and U.S. Pat. No. 6,290,044 discloses
a selectable one-way clutch assembly for use in an automatic
transmission.
[0012] U.S. Pat. Nos. 7,258,214 and 7,344,010 disclose overrunning
coupling assemblies, and U.S. Pat. No. 7,484,605 discloses an
overrunning radial coupling assembly or clutch.
[0013] A properly designed controllable OWC can have near-zero
parasitic losses in the "off" state. It can also be activated by
electro-mechanics and does not have either the complexity or
parasitic losses of a hydraulic pump and valves.
[0014] Other related U.S. patent publications include:
2015/0014116; 2011/0140451; 2011/0215575; 2011/0233026;
2011/0177900; 2010/0044141; 2010/0071497; 2010/0119389;
2010/0252384; 2009/0133981; 2009/0127059; 2009/0084653;
2009/0194381; 20009/0142207; 2009/0255773; 2009/0098968;
2010/0230226; 2010/0200358; 2009/0211863; 2009/0159391;
2009/0098970; 2008/0223681; 2008/0110715; 2008/0169166;
2008/0169165; 2008/0185253; 2007/0278061; 2007/0056825;
2006/0252589; 2006/0278487; 2006/0138777; 2006/0185957;
2004/0110594; and the following U.S. Pat Nos. 9,874,252; 9,732,809;
8,888,637; 7,942,781; 7,806,795; 7,695,387; 7,690,455; 7,491,151;
7,484,605; 7,464,801; 7,349,010; 7,275,628; 7,256,510; 7,223,198;
7,198,587; 7,093,512; 6,953,409; 6,846,257; 6,814,201; 6,503,167;
6,328,670; 6,692,405; 6,193,038; 4,050,560; 4,340,133; 5,597,057;
5,918,715; 5,638,929; 5,342,258; 5,362,293; 5,678,668; 5,070,978;
5,052,534; 5,387,854; 5,231,265; 5,394,321; 5,206,573; 5,453,598;
5,642,009; 6,075,302; 6,065,576; 6,982,502; 7,153,228; 5,846,257;
5,924,510; and 5,918,715.
[0015] A linear motor is an electric motor that has had its stator
and rotor "unrolled" so that instead of producing a torque
(rotation) it produces a linear force along its length. The most
common mode of operation is as a Lorentz-type actuator, in which
the applied force is linearly proportional to the current and the
magnetic field. U.S. published application 2003/0102196 discloses a
bi-directional linear motor.
[0016] Linear stepper motors are used for positioning applications
requiring rapid acceleration and high speed moves with low mass
payloads. Mechanical simplicity and precise open look operation are
additional features of stepper linear motor systems.
[0017] A linear stepper motor operates on the same electromagnetic
principles as a rotary stepper motor. The stationary part or platen
is a passive toothed steel bar extending over the desired length of
travel. Permanent magnets, electro-magnets with teeth, and bearings
are incorporated into the moving elements or forcer. The forcer
moves bi-directionally along the platen, assuring discrete
locations in response to the state of the currents in the field
windings. In general, the motor is two-phase, however a larger
number of phases can be employed.
[0018] The linear stepper motor is well known in the prior art and
operates upon established principles of magnetic theory. The stator
or platen component of the linear stepper motor consists of an
elongated, rectangular steel bar having a plurality of parallel
teeth that extends over the distance to be traversed and functions
in the manner of a track for the so-called forcer component of the
motor.
[0019] The platen is entirely passive during operation of the motor
and all magnets and electromagnets are incorporated into the forcer
or armature component. The forcer moves bi-directionally along the
platen assuming discrete locations in response to the state of the
electrical current in its field windings.
[0020] U.S. patent documents assigned to the same assignee as the
present application and which are related to the present
application include U.S. Pat. Nos. 8,813,929; 8,888,637; 9,109,636;
9,121,454, 9,186,977; 9,303,699; 9,435,387; and U.S. published
applications 2012/0149518; 2013/0256078; 2013/0277164;
2014/0100071; and 2015/0014116. The disclosures of all of the
above-noted, commonly assigned patent documents are hereby
incorporated in their entirety by reference herein.
[0021] Some of the above related patent documents assigned to the
assignee of the present application disclose a 2-position, linear
motor eCMD (electrically controllable mechanical diode). This
device is a dynamic one-way clutch as both races (i.e. notch and
pocket plates) rotate. The linear motor or actuator moves which, in
turn, moves plungers coupled to struts, via a magnetic field
produced by a stator. The actuator has a ring of permanent magnets
that latches the clutch into two states, ON and OFF. Power is only
consumed during the transition from one state to the other. Once in
the desired state, the magnet latches and power is cut.
[0022] U.S. patent documents 2015/0000442; 2016/0047439; and U.S.
Pat. No. 9,441,708 disclose 3-position, linear motor,
magnetically-latching, 2-way CMDs.
[0023] Mechanical forces that are due to local or distant magnetic
sources, i.e. electric currents and/or permanent magnet (PM)
materials, can be determined by examination of the magnetic fields
produced or "excited" by the magnetic sources. A magnetic field is
a vector field indicating at any point in space the magnitude and
direction of the influential capability of the local or remote
magnetic sources. The strength or magnitude of the magnetic field
at a point within any region of interest is dependent on the
strength, the amount and the relative location of the exciting
magnetic sources and the magnetic properties of the various mediums
between the locations of the exciting sources and the given region
of interest. By magnetic properties one means material
characteristics that determine "how easy" it is to, or "how low" a
level of excitation is required to, "magnetize" a unit volume of
the material, that is, to establish a certain level of magnetic
field strength. In general, regions which contain iron material are
much easier to "magnetize" in comparison to regions which contain
air or plastic material.
[0024] Magnetic fields can be represented or described as three
dimensional lines of force, which are closed curves that traverse
throughout regions of space and within material structures. When
magnetic "action" (production of measurable levels of mechanical
force) takes place within a magnetic structure these lines of force
are seen to couple or link the magnetic sources within the
structure. Lines of magnetic force are coupled/linked to a current
source if they encircle all or a portion of the current path in the
structure. Force lines are coupled/linked to a PM source if they
traverse the PM material, generally in the direction or the
anti-direction of the permanent magnetization. Individual lines of
force or field lines, which do not cross one another, exhibit
levels of tensile stress at every point along the line extent, much
like the tensile force in a stretched "rubber band," stretched into
the shape of the closed field line curve. This is the primary
method of force production across air gaps in a magnetic machine
structure.
[0025] One can generally determine the direction of net force
production in portions of a magnetic machine by examining plots of
magnetic field lines within the structure. The more field lines
(i.e. the more stretched rubber bands) in any one direction across
an air gap separating machine elements, the more "pulling" force
between machine elements in that given direction.
[0026] Metal injection molding (MIM) is a metalworking process
where finely-powdered metal is mixed with a measured amount of
binder material to comprise a `feedstock` capable of being handled
by plastic processing equipment through a process known as
injection mold forming. The molding process allows complex parts to
be shaped in a single operation and in high volume. End products
are commonly component items used in various industries and
applications. The nature of MIM feedstock flow is defined by a
physics called rheology. Current equipment capability requires
processing to stay limited to products that can be molded using
typical volumes of 100 grams or less per "shot" into the mold.
Rheology does allow this "shot" to be distributed into multiple
cavities, thus becoming cost-effective for small, intricate,
high-volume products which would otherwise be quite expensive to
produce by alternate or classic methods. The variety of metals
capable of implementation within MIM feedstock are referred to as
powder metallurgy, and these contain the same alloying constituents
found in industry standards for common and exotic metal
applications. Subsequent conditioning operations are performed on
the molded shape, where the binder material is removed and the
metal particles are coalesced into the desired state for the metal
alloy.
[0027] A "moment of force" (often just moment) is the tendency of a
force to twist or rotate an object. A moment is valued
mathematically as the product of the force and a moment arm. The
moment arm is the perpendicular distance from the point or axis of
rotation to the line of action of the force. The moment may be
thought of as a measure of the tendency of the force to cause
rotation about an imaginary axis through a point.
[0028] In other words, a "moment of force" is the turning effect of
a force about a given point or axis measured by the product of the
force and the perpendicular distance of the point from the line of
action of the force. Generally, clockwise moments are called
"positive" and counterclockwise moments are called "negative"
moments. If an object is balanced then the sum of the clockwise
moments about a pivot is equal to the sum of the counterclockwise
moments about the same pivot or axis.
[0029] For purposes of this application, the term "coupling" should
be interpreted to include clutches or brakes wherein one of the
plates is drivably connected to a torque delivery element of a
transmission and the other plate is drivably connected to another
torque delivery element or is anchored and held stationary with
respect to a transmission housing. The terms "coupling," "clutch"
and "brake" may be used interchangeably.
SUMMARY OF EXAMPLE EMBODIMENTS
[0030] An object of at least one embodiment of the present
invention is to provide an overrunning, non-friction coupling and
control assembly, an engageable coupling assembly, and one or more
locking members for use in such assemblies wherein at least one of
the locking members has a centroid which is offset from a pivot
axis of the locking member thereby making the locking member easier
to move at high rotational speeds.
[0031] In carrying out the above object and other objects of at
least one embodiment of the present invention, a locking member for
controllably transmitting torque between first and second coupling
members of a coupling assembly is provided. The first coupling
member includes a coupling face having a pocket which is sized and
shaped to receive and nominally retain the locking member. The
locking member includes a member-engaging first end surface, a
member-engaging second end surface and an elongated main body
portion between the end surfaces. The main body portion is
configured to enable pivotal motion of the locking member about a
pivot axis. The end surfaces of the locking member are movable
between engaged and disengaged positions with respect to the
coupling members during the pivotal motion whereby one-way torque
transfer may occur between the coupling members. A centroid of the
locking member is offset from the pivot axis so that as the locking
member moves from the engaged position, a moment arm of the
centroid relative to the pivot axis decreases from a maximum value
to substantially zero in the disengaged position to facilitate
disengagement of the locking member.
[0032] The main body portion may include a projecting ball-shaped
portion to enable the pivotal motion.
[0033] The locking member maybe a radial locking member.
[0034] The pivot axis maybe located at substantially a center of
the ball-shaped portion.
[0035] The main body portion may include a projecting ball-shaped
portion offset from the centroid and adapted to be received within
a pocket portion of the first coupling member to enable the pivotal
motion. The first coupling member may be adapted to be pivotally
connected to the locking member via the ball-shaped portion.
[0036] The locking member may be a strut such as a ball-socket
strut.
[0037] Further in carrying out the above object and other objects
of at least one embodiment of the present invention, an engageable
coupling assembly is provided. The assembly includes first and
second coupling members. The first coupling member has a coupling
face with a pocket which is sized and shaped to receive and
nominally retain a locking member. The locking member includes a
member-engaging first end surface, a member-engaging second end
surface and an elongated main body portion between the end
surfaces. The main body portion is configured to enable pivotal
motion of the locking member about a pivot axis. The end surfaces
of the locking member are movable between engaged and disengaged
positions with respect to the coupling members during the pivotal
motion whereby one-way torque transfer may occur between the
coupling members. A centroid of the locking member is offset from
the pivot axis so that as the locking member moves from the engaged
position, a movement arm of the centroid relative to the pivot axis
decreases from a maximum value to substantially zero in the
disengaged position to facilitate disengagement of the locking
member.
[0038] The main body portion may include a projecting ball-shaped
portion to enable the pivotal motion.
[0039] The first coupling member may include a socket portion to
receive and retain the ball-shaped portion at a ball and socket
interface and to enable the pivotal motion.
[0040] The locking member may be a strut such as a ball-socket
strut.
[0041] Still further is carrying out the above object and other
objects of at least one embodiment of the present invention, an
overrunning coupling and control assembly is provided. The assembly
includes first and second coupling members. The first coupling
member has a first face with a pocket which is sized and shaped to
receive and nominally retain a locking member and a second face
having a passage in communication with the pocket to communicate an
actuating force to the locking member to actuate the locking member
within the pocket so that the locking member moves between engaged
and disengaged positions. The locking member includes a
member-engaging first end surface, a member-engaging second end
surface and an elongated main body portion between the end
surfaces. The main body portion is configured to enable pivotal
motion of the locking member about a pivot axis. The end surfaces
of the locking member are movable between engaged and disengaged
positions with respect to the coupling members during the pivotal
motion whereby one-way torque transfer may occur between the
coupling members. A centroid of the locking member is offset from
the pivot axis so that as the locking member moves from the engaged
position, a moment arm of the centroid relative to the pivot axis
decreases from a maximum value to substantially zero in the
disengaged position to facilitate disengagement of the locking
member from the second coupling member.
[0042] The main body portion may include a projecting ball-shaped
portion to enable the pivotal motion.
[0043] The assembly may further comprise a linear actuator received
within the passage to provide the actuating force.
[0044] The linear actuator may comprise a solid plunger which moves
between first and second axial positions to control an operating
mode of the assembly. The locking member may be biased to move from
the engaged position towards the disengaged position by a biasing
member.
[0045] The biasing member may comprise a return spring to exert a
spring force on the locking member in opposition to the actuating
force and a friction force at the ball and socket interface.
[0046] While exemplary embodiments are described above, it is not
intended that these embodiments describe all possible forms of the
invention. Rather, the words used in the specification are words of
description rather than limitation, and it is understood that
various changes may be made without departing from the spirit and
scope of the invention. Additionally, the features of various
implementing embodiments may be combined to form further
embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] FIG. 1 is a schematic view, partially broken away of an
overrunning, non-friction, radial coupling and control assembly for
coupling torque between either first and second gears and an output
shaft;
[0048] FIG. 2 is an enlarged view of the view of FIG. 1 to show
details of the coupling and control assembly;
[0049] FIG. 3 is an end schematic view showing spring-biased,
locking members or pawls in various pivotal positions including
coupling and uncoupling positions as actuated by cam surfaces of
cams;
[0050] FIG. 4 is an end schematic view of a second embodiment with
locking members or pawls in various pivotal positions including
coupling and uncoupling positions as actuated by cam surfaces of
cams;
[0051] FIG. 5 is an enlarged side view, partially broken away, of
one of the locking members or cams of FIG. 4 in its coupling
position as actuated by a cam surface of a cam;
[0052] FIG. 6 is an enlarged side view, partially broken away, of
another embodiment of one of the locking members or cams in its
uncoupling position;
[0053] FIG. 7 is a view similar to the view of FIG. 6 but with the
locking member in its coupling position as actuated by a cam
surface of cam;
[0054] FIG. 8 is a view, similar to the views of FIGS. 5 and 7,
which shows a return spring and frictional and return spring
moments operating on the teeter-totter strut;
[0055] FIG. 9 is an enlarged side view, partially broken away, of
another embodiment of one of the locking members in its coupling
position via solid lines and in its uncoupling position with dashed
lines;
[0056] FIG. 10 is a side view, partially broken away, illustrating
the spring plunger actuation system of FIGS. 1 and 2 and for use
with the locking member of FIG. 8; and
[0057] FIG. 11 is a view, similar to the view of FIG. 10, of a
plunger actuation system for use with the locking member of FIG.
9.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
[0058] As required, detailed embodiments of the present invention
are disclosed herein; however, it is to be understood that the
disclosed embodiments are merely exemplary of the invention that
may be embodied in various and alternative forms. The figures are
not necessarily to scale; some features may be exaggerated or
minimized to show details of particular components. Therefore,
specific structural and functional details disclosed herein are not
to be interpreted as limiting, but merely as a representative basis
for teaching one skilled in the art to variously employ the present
invention.
[0059] An overrunning, non-friction, radial coupling and control
assembly constructed in accordance with at least one embodiment of
the present invention is generally indicated at 10 in FIGS. 1 and
2. The assembly 10 preferably includes one or more radial,
pawl-type clutch assemblies having bearing support.
[0060] The assembly 10 includes a first pair of coupling members 12
and 13. The member 12 is a pocket plate and the member 13 comprises
a notch plate which is integrated with powdered metal first gear 11
which may be mounted for rotation with a shaft 14. The pocket plate
has pockets 16 and the notch plate has notches 17. The members 12
and 13 are supported for rotation relative to one another about a
common rotational axis 15 of an output shaft 19. The member 13 is
supported for rotation on the shaft 19 by bearing 21. The coupling
member 12 is splined to the output shaft 19 via splines 25 for
rotation therewith.
[0061] First locking members or pawls 23 float freely in their
pockets 16 and selectively mechanically couple the first pair of
members 12 and 13 together upon engaging notches 17 to prevent
relative rotation of the first pair of members 12 and 13 with
respect to each other in at least one direction about the axis
15.
[0062] The assembly 10 also includes a second pair of coupling
members 32 and 33 supported for rotation relative to one another
about the common rotational axis 15 and second locking members or
pawls 43 which float freely in their pockets 36 for selectively
mechanically coupling the second pair of members 32 and 33 together
to prevent relative rotation of the second pair of members 32 and
33 with respect to each other in at least one direction about the
axis 15. A powdered metal second gear 31 is integrally formed with
the member 33 and is mounted for rotation with the shaft 14. The
member 33 is supported for rotation on the shaft 19 by bearings 41.
The coupling member 32 is splined to the output shaft 19 via
splines 45 for rotation therewith.
[0063] The inner plate-like members 12 and 32 have outer peripheral
surfaces 18 and 38, respectively (FIG. 2). The outer plate-like
members 13 and 33 have inner peripheral surfaces 20 and 40 adjacent
the outer peripheral surface 18 and 38, respectively, in radially
inner and radially outer relationship (FIG. 2). Each of the members
12 and 32 includes the pockets 16 and 36, respectively, angularly
spaced about the axis 15. Each of the pockets 16 and 36 has a
closed end 22 and 42, respectively, and an open end located axially
opposite its closed end 22 or 42 (FIG. 2).
[0064] Each of the pawls 23 and 43 is located in its respective
pocket 16 or 36 and is supported to pivot toward the inner
peripheral surface 20 or 40 of its member 13 or 33. The pawls 23
and 43 are retained within their respective pockets 16 and 36 by
plate-like bushings or retainers 27 and 47 which are secured to
their respective member 12 or 32 via locking or snap rings 28 and
48. The retainers 27 and 47 partially cover the open ends of the
pockets 16 and 36, respectively.
[0065] The inner and outer peripheral surfaces 20 and 18,
respectively, define a first radial bearing interface adjacent the
closed end 22 of each of the pockets 16. The retainer 27 has a
bearing surface 29 which defines a bearing interface adjacent the
open end of each of the pockets 16.
[0066] The inner and outer peripheral surfaces 40 and 38,
respectively, define a second radial bearing interface adjacent the
closed end 42 of each of the pockets 36. The retainer 47 has a
bearing surface 49 which defines a bearing interface adjacent the
open end of each of the pockets 36.
[0067] As best shown in FIG. 3, assembly 10 includes sets of
actuators, generally indicated at 51, including biasing members,
such as springs 50. Each actuator 51 includes a sliding pin 52
having a head 53 received within an aperture formed in the lower
surface of an end portion 54 of its respective pawl 23. An opposite
end portion 55 of each pawl 23 is configured to engage the notches
17. Each of the biasing members 50 urges its respective pin 52 to
move its respective pawl 23 toward the peripheral surface 20 of the
member 13.
[0068] Referring again to FIGS. 1 and 2, the assembly 10 also
includes a 3-position linear stepper motor, generally indicated at
144. The stepper motor 144 is typically controlled by a controller
and includes the stator structure or subassembly 135 including at
least one coil 166 (three shown) to create an electromagnetically
switched magnetic field and to create a magnetic flux when the at
least one coil 166 is energized.
[0069] The stepper motor 144 further includes a
magnetically-latching translator structure or actuator subassembly,
generally indicated at 170, including at least one bi-directionally
movable connecting structure, such as a spring-biased rod or shaft,
generally indicated at 172. Each rod 172 includes a pair of spaced
apart, funnel-shaped cams 174 and 176, each of which has a contour
surface 175 and 177, respectively, to cause the first and second
locking members 23 and 43, respectively, to ride on their
respective contour surfaces 175 and 177 to cause
small-displacement, locking-member pivotal movement between
coupling and uncoupling positions generally as shown in FIG. 3.
[0070] The actuator subassembly 170 further includes a magnetic
actuator, generally indicated at 171, coupled to each rod 172 and
mounted for controlled reciprocating movement along the rotational
axis 15 relative to the first and second pairs of coupling members
12 and 13, and 32 and 33, respectively, between a first extended
position which corresponds to a first mode of the first pair of
coupling members 12 and 13 and a second extended position which
corresponds to a second mode of the second pair of coupling members
32 and 33. The cam 174 actuates the first locking member 23 in its
extended position, so that the first locking member 23 couples the
first pair of coupling members 12 and 13 for rotation with each
other in at least one direction about the rotational axis 15.
[0071] The cam 176 actuates the second locking member 43 to couple
the second pair of coupling members 32 and 33 for rotation with
each other in at least one direction about the rotational axis 15.
The magnetic actuator 171 completes a path of the magnetic flux to
magnetically latch in the first and second extended positions. A
control force caused by the magnetic flux is applied to linearly
move the magnetic actuator 171 between the first and second
extended positions along the rotational axis 15.
[0072] The magnetic actuator 171 preferably includes a permanent
magnet source 178 sandwiched between a pair of annular field
redirection rings 179. The magnetic source 178 is preferably an
annular, rare earth magnet which is axially magnetized.
[0073] In other words, the electromechanical apparatus or motor 144
controls the operating mode of a pair of coupling apparatus, each
of which has drive and driven members supported for rotation
relative to one another about the common rotational axis 15 of the
output shaft 19. Each driven member may be the pocket plate 12 or
32 and the drive member may be the notch plate 13 or 33. Each
coupling apparatus or assembly may include two or more rockers or
pawls 23 or 43 for selectively mechanically coupling the members of
each coupling assembly together and change the operating mode of
each coupling assembly. Preferably, the rockers or pawls 23 and 43
are spaced at intervals about the axis 15 (i.e. FIG. 3).
[0074] The actuator subassembly 170 is configured or adapted for
coupling with the members or plates of both of the coupling
apparatus to rotate therewith. The subassembly 170 is supported on
the output shaft 19 for rotation relative to the coils 166 about
the rotational axis 15. The subassembly 170 typically includes two
or more bi-directionally movable rods or shafts 172. Each stem
portion 180 or 182 of its funnel-shaped cam 174 and 176,
respectively, is adapted to slide within an aperture 184 or 186 in
its respective coupling member during the selective,
small-displacement, locking member pivotal movement. A bushing 188
or 190 may slidably support the stem portions 180 or 182,
respectively, within the apertures 184 and 186.
[0075] The actuator 171 is operatively connected to the rods 172
for selective bi-directional shifting movement along the rotational
axis 15 between a first position of the actuator 171 which
corresponds to a mode (i.e. 1.sup.st gear) of the first coupling
apparatus (plate 12 and plate 13) and a second position of the
actuator 171 which corresponds to a mode (i.e. 2.sup.nd gear) of
the coupling apparatus (plate 32 and plate 33). Two or more rods
172 may be spaced apart from one another as shown in FIG. 3. The
different modes may be locked and unlocked (i.e. free wheeling)
modes and may lock in one or both directions of rotary movement
about the axis 15.
[0076] A first magnetic control force is applied to the actuator
171 when the at least one coil 166 is energized to cause the
actuator 171 to move between its first, second, and neutral
positions along the axis 15.
[0077] The actuator 171 includes a pair of spaced biasing spring
members 192 and 194 for each rod 172 for exerting corresponding
biasing forces on an I-shaped hub or support 196 in opposite
directions along the axis 15 when the hub 196 moves between its
first, second and third positions along the axis 15. The hub 196
has holes 197 for slideably receiving and supporting the connecting
rods or shafts 172. When the support 196 moves, it pushes/pulls its
respective springs 192 and 194 between opposite faces 195 of the
support 196 and cylindrical portions 193 of the funnel-shaped cams
174 and 176.
[0078] The hub 196 rotates with the shaft 19 about the rotational
axis 15. The hub 196 slideably supports interconnecting shaft
portions 199 of the shafts 172 during corresponding shifting
movement along the rotational axis 15 via bushings 198 mounted
within the holes 197.
[0079] The member 12 may include spaced stops to define the
extended positions of the actuator 171.
[0080] The actuator 171 also preferably includes a set of spaced
guide pins (not shown) sandwiched between inner surface of the
member 12 and an outer surface of the hub 196 and extending along
the rotational axis 15. The inner surface and the outer surface may
have V-shaped grooves or notches (not shown) formed therein to hold
the guide pins. The hub 196 slides on the guide pins during
shifting movement of the hub 196 along the rotational axis 15. The
guide pins pilot the hub 196 on the member 12. The hub 196 may also
distribute oil to the guide pins.
[0081] The stator subassembly 135 includes a ferromagnetic housing
167 having spaced apart fingers 168 and the electromagnetically
inductive coils 166 housed between adjacent fingers 168.
[0082] The actuator 171 is an annular part having a magnetic
annular ring 178 sandwiched between a pair of ferromagnetic backing
rings 179. The magnetic control forces magnetically bias the
fingers 168 and their corresponding backing rings 179 into
alignment upon coil energization. These forces latch the actuator
171 in the two "on" or extended positions and the "off" or neutral
position. The rings 179 are acted upon by the stator subassembly
135 to move the actuator 171.
Axial Translation Latching Force in the Permanent Magnet (PM)
Linear Motor (Taken from U.S. Pat. No. 9,435,387)
[0083] Consider the magnetic field line plot, also referred to as a
magnetic flux line plot, shown in the cross-sectional view of the
subject linear motor structure in FIG. 13 of U.S. published
application No. 2015/0014116. This is a circularly symmetric
machine structure, with the translator axial movement direction
shown in the x-direction, and the radial direction shown in the
y-direction. The stator 24,28 cross section is a three iron tooth
72, two slot/coil 26 structure with the slot openings facing,
across a radial air gap, the moving element or translator. The
translator structure includes a single, axially-magnetized, rare
earth PM ring 78 sandwiched between two iron field redirection
rings 80. The sizing of the various components can be estimated
from the scaling, given in meters, on the x and y axes. The
magnetic field lines have been determined by a commercial magnetic
finite element analysis (MFEA) software package. The solution shown
in FIG. 13 is for the case of no coil current in the stator
windings, and a translator axial position somewhat past, to the
right of, the "neutral" or center position. The magnetic field
lines, due to the translator magnet ring 78 alone, are seen to
"flow" in closed paths with the majority of the lines flowing in a
stator iron--air gap--translator iron/magnet circular path.
[0084] In general, the lines of force are confined to paths with a
majority of iron content due to the ease of field production within
the iron material. Examining the field lines that cross the air gap
between the stator and the translator, a majority of them follow a
path, from the translator iron redirection rings, up and to the
right, to the iron teeth members in the stator. Thinking of the
field lines as stretched rubber bands one would then expect a net
force pulling the entire translator to the right. The actual sheer
force density or x-directed sheer stress, again determined from
MFEA analysis, at the axial directed mid-air gap line for this case
is given in FIG. 14A of the above-noted published application.
Shearing stress to both the right and the left is seen in FIG. 14A,
which can be matched to the distribution of air gap field lines
which "lean" to both the right and left along the air gap, but the
total force (the integrated shear over the air gap x-directed
extent) shows a net force on the translator to the right, for this
particular translator position.
[0085] If one "sweeps" the translator position from left to right
and recalculates the field lines at each position one can obtain a
"slide show" of the magnetic field line production due to the
translator position. When the translator structure is located to
the left of the center or neutral position, the majority of the
flux lines flow radially up and to the left of the translator
position, so we expect a left directed force on the translator
body. Conversely, as also shown in FIG. 13, when the translator
structure is located to the right of the center position, the
majority of flux line flow is radially up and to the right, so a
right directed force on the translator body is expected. A plot of
the actual total axial force on the translator body as a function
of axial position, given in Newtons, is shown in FIG. 15A of the
above-noted published application. If the translator is positioned
to the right of center, it is pushed, due to its own magnetic
field, to the right, and if positioned to the left of center, it is
pushed further to the left. This is referred to as the "latching"
action of the assembly. The exact center position, where the
left-right pushing force exactly balances to zero, is an unstable
equilibrium point, at which even minute movements will result in
forces tending to push the translator away from the center
position. The two other points shown, near the two axial ends of
the stator structure, where the net translational force also passes
through a zero value, are stable equilibrium points, where minute
movements result in position restoring force production.
Axial Translation Force in the Permanent Magnet Linear Motor for
the Case of Coil Current (Taken from U.S. Pat. No. 7,435,387)
[0086] Consider the same machine structure as given in FIG. 13 but
with the addition of a steady electrical current in the two stator
windings. The solution for the magnetic field lines for this
situation is shown in FIG. 16 of the above-mentioned application. A
steady current, assumed uniformly distributed in the winding cross
sections, is assumed to flow out of the page, toward the viewer in
the wires of the coil in the slot on right side of the stator. The
axial magnetization direction of the ring magnet did not matter in
the pure latching force situation of FIG. 13 but it matters very
much in this case of "dual" magnetic excitation. For the case
shown, the magnet axial magnetization is stipulated to be to the
right, in the plus x-direction, and therefore the direction or
polarity of the magnetic lines of force closed "flow" path, due to
the magnet alone, would be a counter clockwise circulation. The
polarity direction of the circulating magnetic lines of force due
to an electric current is given by the "right hand rule." If the
thumb of one's right hand is made to point in the direction of the
current flow in a wire, or a coil of wires, with the fingers
encircling the cross section of the wire or the coil, the magnetic
field lines or flux lines also encircle the wire or coil cross
section and have a circulating direction in the same direction as
the curling fingers.
[0087] In FIG. 16 the magnetic lines due the current in the left
side coil alone then encircle this coil in the counter clockwise
direction, while the magnetic lines due to the current in the right
side coil encircle this coil in the clockwise direction. The net or
total production of magnetic field lines, as shown in FIG. 16 is
due to all three magnetic sources, the current in both coils and
the translator magnet, so obviously there are regions in the
machine structure where the individual sources of magnetic
excitation enforce and add with each other and there are regions in
the machine structure where the individual sources of magnetic
excitation buck or subtract from each other. Since the coil current
is reversible (plus or minus) the dual source enforcement and
bucking regions within the machine structure and, most importantly,
within the machine air gap, can be removed with respect to each
other. This is the basis of the controllable/reversible direction
linear motor disclosed herein.
[0088] The flow of the majority of the flux lines produced by the
translator magnet alone resulted in a net force on the translator
to the right for the given translator position shown in FIG. 13.
But for the same translator position, with the addition of the coil
currents, for the case shown in FIG. 16, the flow of the majority
of the flux lines has shifted to a net encirclement of the left
hand coil and the translator structure. So the majority of the flux
lines now cross the air gap up and to the left with respect to the
case confirms this and is shown in the plot of FIG. 17A of the
above-noted published application. If the translator, by means of a
"stop" was, previous to the introduction to translator magnet,
introduction of coil current as in FIG. 16 would then overpower the
latching force to the right and produce a net motoring force to the
left, inducing the translator into left-directed motion. If the
translator does move and subsequently crosses over the center or
neutral position, the motoring or switching current can even then
be removed, as the now left-directed latching force, due to the
magnet alone, will enforce the remaining left movement to a similar
off-state latching position to the left of the center or neutral
position. The net axial separation between the two latched
positions on the left and right of the center position is then said
to be the "stroke" length of the machine.
[0089] A slide show set of solutions for the total magnetic field
lines within the linear motor structure with the same coil current
drive as in the case shown in FIG. 16, as a function of the axial
position of the translator, similar to that given for the previous
case of magnet excitation alone, show that for the level of coil
current assumed the net force on the translator structure is always
to the left, no matter the assumed value of the translator
position.
[0090] Finally, the magnetic field and axial sheer stress solutions
for the case of coil current aiding drive, that is drive in the
direction of the magnet latching force, are given in FIGS. 18 and
19A, respectively of the above-noted published application. The
polarity of the coil currents for the case of FIGS. 18 and 19A are
simply reversed from that of the case shown in FIGS. 16 and 17A,
the translator position is the same as in the case of FIGS. 16 and
17A. In this case, coil current drives in the direction of the
magnet latching force, when the translator position has moved to
the left of the center position.
[0091] Referring now to FIGS. 4 and 5, there is illustrated another
embodiment of a first coupling member 12', notches 17' of a second
coupling member (not shown) and locking members or pawls 23', which
are received and retained with pockets 16' formed within a coupling
face of the coupling member 12'. Parts of the second embodiment
which are the same or similar to parts of the first embodiment have
the same reference numeral but a single prime designation.
[0092] The second embodiment of the overrunning, non-friction
radial coupling and control assembly has substantially the same
parts as the first embodiment except for the parts having a single
prime designation. The assembly preferably includes one or more
radial, pawl-type clutch assemblies having bearing support.
[0093] The coupling and control assembly of the second embodiment
includes the first coupling member or pocket plate 12' and a second
coupling member or notch plate which, as previously mentioned, is
not shown in its entirety but rather its notches 17' are shown for
purposes of simplicity. The first and second members or plates are
supported on rotation relative to one another about a common
rotational axis 15' of an output shaft 19'. The second member is
supported for rotation on the shaft 19' by bearings (not shown) and
the first member 12' is splined to the output shaft 19' via splines
(not shown) for rotation therewith.
[0094] The locking members or pawls 23' are pivotally supported
within their respective pockets 16' by upper and lower cup or
socket portions 200' and 202' of the pocket plate 12'. Each of the
socket portions 200' and 202' has a concave bearing surface 204'
and 206', respectively, adapted to fit against corresponding
bearing surfaces 208' and 210', respectively, of projecting,
convex, upper and lower pivots 212' and 214', respectively, of the
locking member 23'. Preferably, the pivots 212' and 214' provide a
smooth, bulbous, bearing surface for the locking member 23' as it
pivots about its pivot axis 216' between its engaged and disengaged
positions with respect to the coupling members or plates so that
one-way torque transfer can occur between the coupling members.
[0095] The upper and lower pivots 212' and 214', respectively,
extend from a main body portion 218' of the locking member 23'. The
main body portion 218' extends between a member-engaging, first end
surface 220' and a member-engaging, second end surface 222'.
[0096] A centroid or center of mass (i.e. gravity) is substantially
centered on the pivot axis 216' so that the locking member 23' is
substantially centrifugally neutral or balanced. Centrifugal force
acts upon the centroid of the locking member 23' upon rotation of
the pocket plate 12'. The pivot axis 216' is located substantially
at the midpoint between the first and second end surfaces 220' and
222'. If the locking member 23' was not substantially centrifugally
neutral or balanced, the force needed to rotate the locking member
23' would be high at high rotational speeds such as 10,000 RPM.
While it is possible to counteract the locking member imbalance
issue, such measures are oftentimes impractical. By making the
centroid or center of mass of the locking member 23' lie on the
axis of rotation 216' within its pocket 16', the locking member 16'
becomes substantially contrifugally neutral or balanced thereby
making the one-way clutch lighter and more compact.
[0097] One or more biasing members such as springs (not shown) are
disposed in recesses 224' formed in their respective pockets 16' to
bias end portions 54' of their respective locking members 23' and
thereby urge the locking members 23' into their respective pockets
16' in their disengaged positions. The spring forces operate
against the camming forces of the cams 174' as the underside of the
opposite end portions of the locking members 23' ride on the
contour surfaces 175'. As in the first embodiment, a stem portion
180' of the funnel-shaped cam 174' is adapted to slide within an
aperture (not shown in FIGS. 4 and 5) in the pocket plate 12'
during locking member pivotal movement.
[0098] As eCMDs become more accepted as a feasible technology for
Advanced Hybrids and EVs, the specifications and requirements for
the clutches is rapidly increasing. The nature of E-motors is high
torque at zero/low speed with the capability of spinning 3 times
faster than a tradition ICE application. eCMDs need to be able to
turn ON and OFF at speeds of at least 15,000 RPM. The formula for
the radial force generated by rotation is . . .
F.sub.c=MV.sup.2/r
[0099] So the radial force is increased at the square of velocity.
So an example from a design of the strut in a clutch that weighs
4.17 grams at a speed of 15,000 RPM translates into a radial force
of the strut in its pocket of 151 lbs. These are the new realities
that eCMD designers are now faced with. The control system
(electro-mechanical portion) of the eCMD must be able to rotate the
strut in the presence of these huge radial forces. These radial
forces are not reacted by the outer wall of the pocket plate. A
frictional force is generated that creates an opposing moment to
the desired rotation of the strut. The frictional force equation
(formula) is . . .
F.sub.r=.mu.N where N=F.sub.c and .mu.=coefficient of friction
[0100] The opposing moment equation is . . .
M=F.sub.fr
[0101] Where r=the moment arm which is the distance from the pivot
point to the point of contact of the strut to the pocket.
[0102] The lower the value of M, the easier it is for the
electro-mechanical portion of the eCMD to rotate the strut. So for
a given speed of the clutch the parameters that can be manipulated
to reduce the moment are Mass of the strut, the value of .mu. and
the length of the moment arm. The following description is released
to the embodiment of FIGS. 6 and 7 and its objective to reduce the
moment arm.
[0103] Referring now to FIGS. 6 and 7, there is illustrated yet
another embodiment of a first coupling member 12'', notches 17'' of
a second coupling member 13'' and a locking member or pawl 23''
which is received and retained within a pocket 16'' formed within a
coupling face of the coupling member 12''. Parts of the third
embodiment which are the same or similar to parts of the first and
second embodiments, have the same reference number but a double
prime designation.
[0104] The third embodiment of the overrunning, non-friction radial
coupling and control assembly has substantially the same parts as
the first and second embodiments except for the parts having a
double prime designation. The assembly preferably includes one or
more radial, pawl-type clutch assemblies having bearing
support.
[0105] The coupling and control assembly of the third embodiment
includes the first coupling member or pocket plate 12'' and the
second coupling member or notch plate 13'' which, as previously
mentioned, is not shown in its entirety but rather its notches 17''
are shown for purposes of simplicity. The first and second members
or plates are supported on rotation relative to one another about a
common rotational axis of an output shaft (not shown). The second
member is supported for rotation on the shaft by bearings (not
shown) and the first member 12'' is splined to the output shaft via
splines (not shown) for rotation therewith.
[0106] The locking member or pawl 23'' is supported within its
pocket 16'' by upper and lower cup or socket portions 200'' and
202'' of the pocket plate 12''. The socket portion 202'' has a
concave bearing surface 206'', adapted to fit against corresponding
bearing surface 210'', of a projecting, convex, lower pivot 214''
of the locking member 23''. Preferably, the pivot 214'' provides a
smooth, bulbous, bearing surface of the locking member 23'' as it
pivots about its pivot axis 216'' between its engaged and
disengaged positions with respect to the coupling members or plates
so that one-way torque transfer can occur between the coupling
members.
[0107] The design of FIGS. 6 and 7 show a modification to the
radial strut and the pocket of FIGS. 4 and 5. The radial strut is
23'' is a MIM part with a formed oval hole 240'' centered about the
centroid of the strut. The pocket plate has a pressed in hardened
and polished pin 242'' of a diameter of approximately 2 mm. The
width of slot in the oval hold is approximately 2.2 mm. If the pin
242'' was not present, the contact of the radial strut would occur
at point A with a moment arm of C. With the pin 242'' present, the
sliding contact occurs at point B with a moment arm of D. The
advantage is that D is much shorter than C, then M is reduced
linearly with the reduction of length of the moment arm.
[0108] The radial strut 23'' and pin 242'' could both be coated
with a friction reducing coating like Teflon that reduces .mu..
[0109] The reason the pin 242'' is not a tight fit to a hole in the
radial strut 23'' is because when the strut 23'' is locked and
carrying load, there must be clearance to the pin 242''. The
function of the point 242'' is to provide a reaction point when
transitioning from OFF to ON and ON to OFF. It should not be loaded
beyond the load from the radial force generated by rotation, hence
the oval clearance hole 240''.
[0110] The lower pivot 214'' extends from a main body portion 218''
of the locking member 23''. The main body portion 218'' extends
between a member-engaging, first end surface 220'' and a
member-engaging, second end surface 222''.
[0111] A centroid or center of mass (i.e. gravity) is substantially
centered on the pivot axis 216'' so that the locking member 23'' is
substantially centrifugally neutral or balanced. Centrifugal force
acts upon the centroid of the locking member 23'' upon rotation of
the pocket plate 12''. The pivot axis 216'' is located
substantially at the midpoint between the first and second end
surfaces 220'' and 222''. If the locking member 23'' is
substantially centrifugally neutral or balanced, the force needed
to rotate the locking member 23'' is high at high rotational speeds
such as 10,000 RPM. While it is possible to counteract the locking
member imbalance issue, such measures are oftentimes impractical.
By making the centroid or center of mass of the locking member 23''
lie on the axis of rotation 216'' within its pocket 16'', the
locking member 23'' becomes substantially contrifugally neutral or
balanced thereby making the one-way clutch lighter and more
compact.
[0112] One or more biasing members such as springs (not shown) are
disposed in a recess 224'' formed in its pockets 16'' to bias end
portions 54'' of the locking member 23'' and thereby urge the
locking member 23'' into its pockets 16'' in its disengaged
positions. The spring force operates against the camming forces of
the cam 174'' as the underside of the opposite end portions of the
locking member 23'' ride on the contour surface 175''. As in the
first embodiment, a stem portion 180'' of the funnel-shaped cam
174'' is adapted to slide within an aperture (not shown in FIGS. 6
and 7) in the pocket plate 12'' during locking member pivotal
movement.
[0113] Referring now to FIG. 8, a "teeter-totter" locking member or
strut, generally indicated at 323, is shown in its coupled position
between its pocket plate 312 and its notch plate 313 of its clutch
assembly, generally indicated at 311. Theoretically, there is no
net moment trying to rotate the strut 323 in either direction while
the clutch is rotating. Rotating the strut 323 to the `OFF`
position is accomplished via a return spring 325 disposed in a
recess 324 and acting directly on the strut 323. The return spring
325 (see return spring moment 313) must overcome frictional forces
(see frictional moment 315) to ensure that the strut 323 disengages
from a notch 317 of the notch plate 313.
[0114] The spring plunger actuator system of FIGS. 1, 2 and 10 is
`fire and forget` as its plunger or rod 172 is biased by a spring
194 to provide an `ON` force to the strut 323 in a tooth-butt
condition. Thus, the strut 323 will engage as soon as relative
motion between the plates 312 and 313 allows notch
availability.
[0115] In other words, a center of gravity (i.e. CG) of the strut
323 and the rotation axis 316 of the strut 323 are co-located in
the same position. That means that there is no moment arm between
the CG and the pivot point 316 of the strut 323 as shown in FIG. 8.
With no moment arm, then there is no moment generated by the CG
attempting to rotate the strut 323.
[0116] When turning the clutch assembly 311 OFF at a high
rotational velocity, the only forces and their corresponding
moments acting on the rotation of the strut 323 is the return
spring 325 creating the OFF spring moment 313 and the frictional
moment 315 acting in the ON (opposite) direction. In order for the
strut 323 to turn OFF the return spring moment 313 has to be
greater than that of the frictional moment 315. If the coefficient
of friction between the strut 323 and pocket plate 312 is low, then
the net moment on the strut 323 turns the strut 323 OFF. Oil,
surface finish, imperfect location of the CG to the rotation point
316 all can contribute to conditions where the sum of the moments
opposing the return spring moment 313 overcome the return spring
moment 313. This would result in the strut 323 not rotating to the
OFF position. The clutch assembly 311 may not turn OFF after the
actuator system is stroked to the OFF position. This means that the
return spring moment 313 acting to turn OFF the strut 323 at about
9000 RPM or higher is not robust. The net OFF moment needs to be
increased to ensure that the strut 323 will turn OFF 100% of the
time.
[0117] Referring now to FIGS. 9 and 11, a ball-socket locking
member strut, generally indicated at 423, is constructed in
accordance with at least one embodiment of the present invention.
The ball-socket strut 423 has a center of gravity 417 which is
offset from a point of rotation or axis 416, resulting in a net
`OFF` moment when the clutch assembly, generally indicated at 411,
rotates.
[0118] A return spring 425 acts directly on the strut 423 and is
used in addition to the new strut moment (i.e. centroid moment arm
419) to help turn the strut 423 "OFF". In this way, OFF force is
significantly increased to reliably disengage the strut 423 from
its clutch or notch plate 413.
[0119] As a result, a larger `ON` force is now required from an
actuation system, generally indicated at 430 in FIG. 11, to
overcome this increased `OFF` force. The summation of these new
"OFF" forces would overpower the spring 194 of the actuation system
of FIG. 10 and would render the magnetic latch of the system
inadequate during tooth-butt conditions. The system of FIG. 10 is
modified to obtain the system 430 of FIG. 11 as described
hereinbelow.
[0120] The system 430 is not a `fire and forget` system like the
system of FIG. 10 thereby allowing for the use of the "Solid
Plunger" system 430 of FIG. 11. The solid plunger actuation system
430 has fewer components compared to the system of FIG. 10 which
has the spring 194, a plunger, a sleeve or bearing 198 and plunger
fasteners (not shown).
[0121] The locking member or strut 423 of FIG. 9 has the following
features:
[0122] 1) Its ball and socket design keeps contact between the
strut 423 and its pocket plate 412 confined to the ball and socket
interface except for when the strut 423 is in its locked or engaged
position as shown in FIG. 9. The purpose of this is to keep the
frictional moment arm small (between the ball and socket) until the
full stroke of the actuation system 430 is reached going from OFF
to ON. This keeps the contact face off the back wall of the pocket
while rotating until the ON position is reached. This reduces the
axial force requirements of the linear motor activation system 430
of FIG. 11 while turning ON and aids the return spring 425 and
centrifugal moment when turning OFF.
[0123] 2) The wrap of the pocket plate 412 (socket) around a ball
(toe) portion 421 of the strut 423 is far enough to retain the
strut 423 in its pocket in the pocket plate 412. This aids the
function of #1 immediately above and traps the strut 423 in the
pocket.
[0124] 3) The CG forms a moment arm in the ON position of the strut
423 such that: (1) the moment arm 419 is at its max length 419 for
the range of rotation in the ON position and (2) at the OFF
position, the length of the moment arm 419 from CG is zero (in the
phantom position). This feature ensures a max moment 419 in the OFF
direction when the strut 423 is full ON (solid lines) and no OFF
moment when the strut 423 is in the OFF position (phantom lines)
making it easier for the linear motor of the actuation system 430
to get the strut 423 rotating when turning ON.
[0125] (4) The "rocker-like" shape of the strut 423 is
differentiated from prior art rockers or struts in important ways:
(1) The shape is designed specifically for a radial CONTROLLABLE
clutch as disclosed herein; (2) The strut 423 is for a 2-way clutch
and is not passive; (3) The strut 423 does not overrun, it is
turned OFF and kept OFF when not transmitting torque; and (4) The
strut 423 has more wrap around the toe (i.e. ball portion 421) of
the strut 423 to create a true ball and socket type joint.
[0126] As previously mentioned, the strut 423 has a strut geometry
wherein its CG 417 is not co-located at its rotation point or axis
416. The CG location relative to the rotation point 416 provides
the maximum length moment arm 419 in the ON position that creates a
centrifugal OFF moment on the strut 423. This centrifugal OFF
moment is additive to the return spring moment. The sum of these 2
moments now more than overcomes the frictional moment at about 9000
RPM and higher ensuring that the strut 423 turns OFF. As the strut
423 rotates from ON to OFF, the moment arm 419 of the CG 417
relative to the rotation point 416 of the strut 427 decreases such
that at full OFF, the moment arm length 419 is zero, thus no
centrifugal force at the OFF position. This feature aids the
activation system 430 to get the actuator moving from OFF to ON
easier. There is no centrifugal resistance initially to get the
strut 423 moving from OFF to ON.
[0127] The strut 423 solves the previously mention OFF problem at
high speed disengagement. However, this adds more required axial
force of the actuator of the actuation system plunger 476 going
from OFF to ON to overcome these new OFF forces. The actuation
system 430 does away with the "fire and forget" control
strategy/function of the prior actuation system and use the ON
stator forces to stroke the actuator from a tooth-butt condition to
an ON position. When using the coil 166 to get the clutch to go ON
means that the system 430 is different from the actuation system of
FIG. 10 in the following ways: [0128] The stator subassembly 135
now stays on longer to give the races or coupling members 412 and
413 the needed time to rotate into a locked state. [0129] For a
given time the stator subassembly 135 is ON, there must be a
minimum relative speed between the races 412 and 413 to rotate out
of the tooth-butt position to the locked position. The max distance
(S=RO) the strut 423 has to move relative to the notches of the
notch plate 413 is equal to the backlash of the clutch 411 in
radians.times.radius of the notch plate ID/OD. [0130] The "fire and
forget" function no longer exist, so the need for the plunger
spring 194 is eliminated. This is where the "solid plunger" of FIG.
11 come into play. [0131] The control strategy gets more
complicated when eliminating "fire and forget." [0132] Plunger
sleeves are also eliminated because there is no longer relative
movement between the plungers and the actuator. [0133] The ON
magnetic latch requirements can be reduced slightly because they no
longer have the requirement to drive the actuator ON from the
tooth-butt position. The only function of the latch is to hold ON
and OFF.
[0134] While exemplary embodiments are described above, it is not
intended that these embodiments describe all possible forms of the
invention. Rather, the words used in the specification are words of
description rather than limitation, and it is understood that
various changes may be made without departing from the spirit and
scope of the invention. Additionally, the features of various
implementing embodiments may be combined to form further
embodiments of the invention.
* * * * *